Analytical fluid sample systems are used to prepare and condition a fluid sample stream for analysis as part of a analytical fluid system. A common but not exclusive application is analysis of gas sample streams. The sample streams may be analyzed using a gas chromatograph or other analyzer. Each fluid sample stream is conditioned by the fluid sample system prior to the sample stream being received and processed by the analyzer. In cases where the fluid may be flammable or should be contained, the fluid sample system is physically disposed within a hazardous area that is isolated from the surrounding ambient environment. The ambient environment outside the hazardous area is commonly referred to as a safe area. Between the hazardous area and the safe area is a barrier that physically isolates the safe area from the hazardous area. The barrier may be an electrical barrier that limits power and heat in order to prevent an incendiary condition, and/or a physical barrier such as an explosion proof or pressurized/purged enclosure, as is known.
The fluid sample system conditions the sample streams in the hazardous area by regulating pressure of the sample streams and filtering the sample streams as is known. In addition, the fluid sample system may monitor in the hazardous area various sample stream parameters such as pressure, temperature and flow rate. Various electrical signals are typically produced in the hazardous area that relate to the parametric information from pressure sensors, proximity sensors and temperature sensors. Sensors and actuators such as for valves in the hazardous area must be intrinsically safe (i.e. incapable of igniting flammable vapors), explosion proof or purged/pressurized.
In known analytical fluid systems, the analyzer is disposed in the safe area, meaning that the conditioned fluid sample stream and the parametric signals must cross over the barrier in a safe manner to maintain the integrity of the boundary between the hazardous side and the safe side. Furthermore, a control system that is used to control and/or monitor operation of the fluid sample system, for example various valves and sensors, is fully disposed in the safe area. Thus, the control and output signals also must cross the barrier in a safe manner. Each location of crossing the barrier must be done with a dedicated safe coupling or connection—this includes each parametric electrical signal, each pneumatic signal, each control signal and the fluid sample stream.